Radio frequency screen for an ultraviolet lamp system

ABSTRACT

A radio frequency (RF) screen for a microwave powered ultraviolet (UV) lamp system is disclosed. In one example, a disclosed RF screen includes: a sheet comprising a conductive material; and a frame around edges of the sheet. The conductive material defines a predetermined mesh pattern of individual openings across substantially an operative area of the screen. Each of the individual openings has a triangular shape.

BACKGROUND

Ultraviolet (UV) lamp systems may be used in semiconductor manufacturingprocesses to cure inks, coatings, photoresists, and adhesives in avariety of applications. These applications may include, for instance,decorating, laminating, hard-coat protection, circuit board conformalcoatings, photoresist, photolithography, printing, and solar simulation.A UV lamp produces high intensity radiation energy in the UV, visible,and infrared spectrums. This high intensity radiation energy may be usedto cure inks, coatings, photoresists, and adhesives that are applied toa variety of substrates, such as paper, plastic film, wood, and metal.

A microwave powered UV lamp system has an irradiator to convertelectrical power to radio frequency (RF) energy. The microwave energy orRF energy is guided into a cavity where a UV bulb is positioned toabsorb the RF energy and change to a plasma state. The plasma producesradiation energy in the UV lamp system in the form of UV light. Themicrowave powered UV lamp system has an RF screen with openings tocapture and seal the RF energy within the cavity while permitting lightenergy to be transmitted through the screen openings.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments of the present disclosure are described indetail below with reference to the following Figures. The drawings areprovided for purposes of illustration only and merely depict exemplaryembodiments of the present disclosure to facilitate the reader'sunderstanding of the present disclosure. Therefore, the drawings shouldnot be considered limiting of the breadth, scope, or applicability ofthe present disclosure. It should be noted that for clarity and ease ofillustration these drawings are not necessarily drawn to scale.

FIG. 1 illustrates a cross sectional view of an exemplary UV lamp systemhaving an RF screen, in accordance with some embodiments of the presentdisclosure.

FIG. 2 illustrates a perspective view of an exemplary RF screen attachedto a reflector, in accordance with some embodiments of the presentdisclosure.

FIG. 3 illustrates a top view of an exemplary RF screen, in accordancewith some embodiments of the present disclosure.

FIG. 4 illustrates exemplary shapes of RF screen openings, in accordancewith some embodiments of the present disclosure.

FIGS. 5-8 illustrate exemplary mesh patterns of RF screen openings inthe shape of isosceles right triangles, in accordance with someembodiments of the present disclosure.

FIGS. 9-12 illustrate exemplary mesh patterns of RF screen openings inthe shape of right triangles, in accordance with some embodiments of thepresent disclosure.

FIGS. 13-14 illustrate exemplary mesh patterns of RF screen openings inthe shape of isosceles triangles, in accordance with some embodiments ofthe present disclosure.

FIGS. 15-16 illustrate exemplary mesh patterns of RF screen openings inthe shape of equilateral triangles, in accordance with some embodimentsof the present disclosure.

FIG. 17 illustrates a flow chart of a method for performing a UV induceddeposition, in accordance with some embodiments of the presentdisclosure.

DETAIL DESCRIPTION

Various exemplary embodiments of the present disclosure are describedbelow with reference to the accompanying figures to enable a person ofordinary skill in the art to make and use the present disclosure. Aswould be apparent to those of ordinary skill in the art, after readingthe present disclosure, various changes or modifications to the examplesdescribed herein can be made without departing from the scope of thepresent disclosure. Thus, the present disclosure is not limited to theexemplary embodiments and applications described and illustrated herein.Additionally, the specific order and/or hierarchy of steps in themethods disclosed herein are merely exemplary approaches. Based upondesign preferences, the specific order or hierarchy of steps of thedisclosed methods or processes can be re-arranged while remaining withinthe scope of the present disclosure. Thus, those of ordinary skill inthe art will understand that the methods and techniques disclosed hereinpresent various steps or acts in a sample order, and the presentdisclosure is not limited to the specific order or hierarchy presentedunless expressly stated otherwise.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly. Terms such as“attached,” “affixed,” “connected” and “interconnected,” refer to arelationship wherein structures are secured or attached to one anothereither directly or indirectly through intervening structures, as well asboth movable or rigid attachments or relationships, unless expresslydescribed otherwise.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Reference will now be made in detail to the present embodiments of thedisclosure, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers are used in thedrawings and the description to refer to the same or like parts.

The present disclosure provides a RF screen in a UV lamp system toprovide better reliability and higher light output. The disclosed RFscreen has a mesh pattern of individual openings across substantially anoperative area of the screen. According to various embodiments of thepresent teaching, the screen openings are in the shape of triangles,e.g. isosceles triangles, equilateral triangles, right triangles, and/orscalene triangles. In one embodiment, the individual openings of the RFscreen are in the shape of multiple types of triangles. The triangles intwo adjacent rows of the mesh pattern may or may not be aligned to eachother. Compared to RF screens with rectangular, square, or hexagonalopenings, the disclosed RF screen with triangular openings can sustain ahigher stress, have a lower deformation, and thus have a betterreliability. In addition, the disclosed RF screen can achieve a betterUV light transmittance, i.e. higher UV light output through the RFscreen, which improves the efficiency of the UV lamp system and reducesthe amount of downtime to the UV lamp system.

FIG. 1 illustrates a cross sectional view of an exemplary UV lamp system100 having an RF screen 108, in accordance with some embodiments of thepresent disclosure. In some embodiments, the UV lamp system 100 heatsand cures materials, such as a material layer (or film) disposed over asubstrate. For simplicity and clarity, FIG. 1 shows only selectedportions of an overall UV lamp system to facilitate an understanding ofaspects of the present disclosure. Additional features can be added inthe UV lamp system 100, and some of the features described below can bereplaced or eliminated for other embodiments of the UV lamp system 100.

As shown in FIG. 1 , the UV lamp system 100 includes a radiationgenerator 110. The radiation generator 110 generates radiation that canbe used to heat or cure a material layer (film) disposed over asubstrate. In one embodiment, the radiation generator 110 is a UV lampmodule. The radiation generator 110 may include dynamic portionsconfigured to move, for example, in a swinging motion, a rotatingmotion, other suitable motion, or combinations thereof.

The radiation generator 110 in this example further includes an energysource 101. The energy source 101 can generate energy to excite aradiation of UV light. For example, the energy source 101 may includeone or more microwave generators, such as magnetrons, that generatemicrowave energy, e.g. radio frequency (RF) microwave energy 102, thatcan excite a radiation of UV light. The energy source 101 may includeone or more transformers to energize filaments of the magnetron. Theenergy source 101 may be coupled to a power supply that provideselectrical power to the energy source 101. The magnetrons in the energysource 101 can convert the electrical power received from the powersupply to microwave energy or RF energy.

The radiation generator 110 in this example further includes a radiationsource 103 coupled with the energy source 101. The energy source 101 maybe coupled to the radiation source 103 via a waveguide 107, whichdirects energy produced by the energy source 101, such as microwaveenergy, to the radiation source 103. In one embodiment, the radiationsource 103 is a UV radiation lamp that includes a UV lamp source 104disposed within a cavity or chamber 105, such as a microwave chamber.The chamber 105 may have an oxygen-free atmosphere to ensure thatradiation generated by the radiation source 103, such as UV radiation,is not absorbed by the chamber environment. The chamber 105 may be avacuum chamber with a suitable temperature maintained within the chamber105.

The UV lamp source 104 housed within the radiation source 103 mayinclude one or more UV bulbs. In one example, each UV bulb is a sealedplasma bulb filled with one or more gases, such as xenon (Xe), mercury(Hg), krypton (Kr), argon (Ar), other suitable gas, or combinationsthereof. The gases used within the UV lamp source 104 may absorb themicrowave (RF) energy and, consequently, change to a plasma state. Theplasma may produce radiation energy in the UV lamp system 100 in theform of UV light. In one embodiment, the gases used within the UV lampsource 104 can be selected such that selected UV radiation wavelengthsare emitted from the radiation source 103. In one embodiment, theselected UV radiation wavelengths are between 200 and 450 nm. As such,energy produced by the energy source 101, such as microwave energy, isdirected by the waveguide 107 to the radiation source 103 to exciteelements of the radiation source 103, such as the gases of the UV lampsource 104, so that the radiation source 103 emits UV radiation 106. Tobe specific, each UV bulb of the UV lamp source 104 can be excited bythe RF energy 102 to emit UV light 106.

The radiation generator 110 in this example further includes an RFscreen 108 attached to the radiation source 103 to encapsulate thecavity 105. The RF screen 108 may include a sheet made of a conductivematerial with a predetermined mesh pattern of individual openings. TheRF screen 108 prevents or blocks the RF energy from escaping andtravelling out of the cavity 105, while permitting UV light 106 to betransmitted through the screen openings. In one embodiment, the openingsin the RF screen 108 are constructed to be smaller than the RF radiationwavelength. In one embodiment, the RF energy has a frequency range ofabout 2445˜2470 MHz.

The radiation generator 110 is coupled to a process portion 120. Theradiation generator 110 and the process portion 120 may collectively bereferred to as a radiation process chamber, or a UV process chamber. Theprocess portion 120 includes a wafer holder 126. The wafer holder 126includes a pedestal for supporting a substrate, such as a substrate 124.The substrate 124 may alternatively be referred to as a material layer,or the substrate 124 may include a material layer disposed thereon thatwill be exposed to the UV radiation 106 from the radiation source 103.The material layer may be a metal layer, a semiconductor layer, or adielectric layer. The wafer holder 126 may include a heating mechanismfor heating the substrate 124. In an example, a position of thesubstrate 124 within the process portion 120 is adjusted by a mechanismof the wafer holder 126 that allows the wafer holder 126 to move withinthe process portion 120. For example, the wafer holder 126 may movevertically, horizontally, or both to position the substrate 124 at aparticular distance from the radiation source 103. Radiation, such as UVlight 106, emitted from the radiation source 103 enters the processportion 120 by passing through a window 122 and exposes the substrate124. The window 122 is thick enough to maintain vacuum. The window 122may further include a material, such as quartz, that transmits theradiation 106.

In one embodiment, the UV lamp system 100 further includes a radiationsensor to detect and convert radiation 106 emitted by the radiationsource 103 into electronic signals that indicate characteristics of thedetected radiation 106, such as an intensity of the detected radiation106, a temperature within the cavity 105, and/or a temperature of thesubstrate 124. Once a characteristic value is above or below apredetermined threshold, the UV lamp system 100 will adjust some controlparameters, e.g. by a blower fan, to modify the characteristic valueback to normal.

FIG. 2 illustrates a perspective view 200 of an exemplary RF screenattached to a reflector in a UV lamp system, e.g. the UV lamp system 100in FIG. 1 , in accordance with some embodiments of the presentdisclosure. As shown in FIG. 2 , a reflector may include a top portion210 and two curved reflecting surfaces 220. The reflector is coupled toa RF screen 240. A cavity is formed by the RF screen 240, the topportion 210, and curved reflecting surfaces 220 of the reflector. A UVbulb 230 is located within the cavity to emit UV light when excited byRF energy. The reflector properly focus the UV light energy emitted fromthe UV bulb 230 contained within the reflector, except allowing the UVlight energy to transmit through the RF screen 240.

In one embodiment, the UV bulb 230 is made of glass; the reflector ismade of glass or quartz. The RF screen 240 may be made of a conductivematerial, e.g. copper, brass, stainless steel, tungsten, aluminum, orother metals or metal alloys.

FIG. 3 illustrates a top view of an exemplary RF screen 300, inaccordance with some embodiments of the present disclosure. As shown inFIG. 3 , the RF screen 300 includes a sheet 310 and a frame 320 aroundedges of the sheet 310. The sheet 310 may include a conductive materialcomprising copper, brass, stainless steel, tungsten, aluminum, nickel,silver, or combinations thereof.

In this example, the sheet 310 has a rectangular shape with four edges,and has a predetermined mesh pattern of individual openings acrosssubstantially an operative area of the RF screen 300. As shown in FIG. 3, the predetermined mesh pattern tiles the rectangular surface of thesheet 310 with a plurality of triangles. Tiling of a surface meansfilling up the surface using one or more geometric shapes, with nooverlaps and no gaps. Each of the individual openings has a triangularshape. The frame 320 is equipped with holes 330 that are utilized forattachment of the RF screen 300 to a UV lamp system. In one embodiment,the predetermined mesh pattern comprises 16 to 36 individual openings ina unit area of 1 square centimeter. In one embodiment, the RF screen 300has a thickness between 0.001 inch and 0.015 inch.

Compared to a reference screen with a mesh pattern comprising individualopenings in the shape of a square, a rectangle, or a hexagon, thedisclosed RF screen 300 with triangular openings can yield an increasein UV light transmittance, a decrease in maximum deformation, and adecrease in maximum stress, when the disclosed RF screen 300 and thereference screen have a same number of individual openings in a unitarea. That is, a RF screen with triangular openings is less likely to bedamaged or deformed, and can provide a higher UV light output throughthe screen, compared to RF screens with openings in the shapes ofsquare, rectangle, and hexagon.

FIG. 4 illustrates exemplary shapes of RF screen openings, in accordancewith some embodiments of the present disclosure. While a RF screen has amesh pattern of individual openings, at least one of the individualopenings has a triangular shape. In one embodiment, each of theindividual openings has a triangular shape.

There are different types of triangles, e.g. an isosceles triangle 410,an equilateral triangle 420, a right triangle 430, an isosceles righttriangle 440, and a scalene triangle 450. An isosceles triangle is atriangle that has two sides of equal length. The two equal sides arecalled the legs and the third side is called the base of the triangle.As such, the isosceles triangle 410 has two legs 411, 412, and a base413. An equilateral triangle is a triangle in which all three sides areequal. As shown in FIG. 4 , the equilateral triangle 420 has three equalsides 421, 422, 423. The equilateral triangle 420 can be treated as aspecial isosceles triangle, with any two sides being legs and the thirdside being a base. A right triangle is a triangle in which one angle isa right angle, i.e. a 90-degree angle. The side opposite the right angleis called the hypotenuse. The sides adjacent to the right angle arecalled legs. As such, the right triangle 430 has two legs 431, 432, anda hypotenuse 433. An isosceles right triangle is both an isoscelestriangle and a right triangle. As shown in FIG. 4 , the isosceles righttriangle 440 has two equal legs 441, 442 adjacent to the right angle,and a base or hypotenuse 443 opposite the right angle. A scalenetriangle is a triangle in which all three sides have different lengths.The angles of a scalene triangle have different measures. As shown inFIG. 4 , the three sides 451, 452, 453 of the scalene triangle 450 havedifferent lengths from each other.

In one embodiment, the individual openings of an RF screen are in theshape of a uniform type of triangle. In one embodiment, the individualopenings of an RF screen are in the shapes of multiple types oftriangles comprising at least one of: an isosceles triangle, a righttriangle, an equilateral triangle, or a scalene triangle.

In one embodiment, the mesh pattern tiles a surface of the RF screenwith multiple geometric shapes including triangle. For example, for a RFscreen having a sheet with a rectangular surface with four edges, themesh pattern may tile the rectangular surface with a plurality oftriangles in proximity of the four edges and a plurality of rectanglesor squares surrounded by the plurality of triangles.

FIGS. 5-8 illustrate exemplary mesh patterns of RF screen openings inthe shape of isosceles right triangles, in accordance with someembodiments of the present disclosure. In each case, the mesh patterncan tile a rectangular surface of a RF screen with some periodic shapes.That is, the rectangular surface can be tiled without overlaps or gapsby repeating the periodic shape via translation only, without a need ofrotating, reflecting or scaling the periodic shape. A translation is ageometric transformation that moves every point of a figure or a shapeby the same distance in a given direction. In one embodiment, theperiodic shape includes a plurality of isosceles right trianglesarranged in a certain pattern, called a repeating pattern. As such, thetiling of each rectangular surface shown in FIGS. 5-8 is a periodictiling having a repeating pattern.

FIG. 5 illustrates a mesh pattern 500 that can tile a rectangularsurface of a RF screen with a plurality of individual openings 510 eachof which is in the shape of an isosceles right triangle. The tiling bythe mesh pattern 500 is a periodic tiling having a repeating pattern520. As shown in FIG. 5 , the repeating pattern 520 is a squareincluding two isosceles right triangles that are side by side via a samebase, which is a diagonal line of the square. The repeating pattern 520is a minimum pattern element that can be repeated to tile therectangular surface based merely on translation of the repeatingpattern, without a need of rotating, reflecting or scaling the repeatingpattern. As such, the mesh pattern 500 can tile the rectangular surfacewith periodic squares each of which is formed by two isosceles righttriangles.

FIG. 6 illustrates a mesh pattern 600 that can tile a rectangularsurface of a RF screen with a plurality of individual openings 610 eachof which is in the shape of an isosceles right triangle. The tiling bythe mesh pattern 600 is a periodic tiling having a repeating pattern620. As shown in FIG. 6 , the repeating pattern 620 is a squareincluding 8 isosceles right triangles. The 8 isosceles right trianglesform 4 pairs each of which includes two isosceles right triangles thatare side by side via a same base. The repeating pattern 620 is a minimumpattern element that can be repeated to tile the rectangular surfacebased merely on translation of the repeating pattern, without a need ofrotating, reflecting or scaling the repeating pattern. As such, the meshpattern 600 can tile the rectangular surface with periodic squares eachof which is formed by 8 isosceles right triangles.

FIG. 7 illustrates a mesh pattern 700 that can tile a rectangularsurface of a RF screen with a plurality of individual openings 710 eachof which is in the shape of an isosceles right triangle. The tiling bythe mesh pattern 700 is a periodic tiling having a repeating pattern720. As shown in FIG. 7 , the repeating pattern 720 is a rectangleincluding 8 isosceles right triangles. The 8 isosceles right trianglesform 4 pairs each of which includes two isosceles right triangles thatare side by side via a same base. The repeating pattern 720 is a minimumpattern element that can be repeated to tile the rectangular surfacebased merely on translation of the repeating pattern, without a need ofrotating, reflecting or scaling the repeating pattern. As such, the meshpattern 700 can tile the rectangular surface with periodic rectangleseach of which is formed by 8 isosceles right triangles.

FIG. 8 illustrates a mesh pattern 800 that can tile a rectangularsurface of a RF screen with a plurality of individual openings 810 eachof which is in the shape of an isosceles right triangle. The tiling bythe mesh pattern 800 is a periodic tiling having a repeating pattern820. As shown in FIG. 8 , the repeating pattern 820 is a rectangleincluding 4 isosceles right triangles. The 4 isosceles right trianglesform 2 pairs each of which includes two isosceles right triangles thatare side by side via a same base. The repeating pattern 820 is a minimumpattern element that can be repeated to tile the rectangular surfacebased merely on translation of the repeating pattern, without a need ofrotating, reflecting or scaling the repeating pattern. As such, the meshpattern 800 can tile the rectangular surface with periodic rectangleseach of which is formed by 4 isosceles right triangles.

FIG. 9 illustrates a mesh pattern 900 that can tile a rectangularsurface of a RF screen with a plurality of individual openings 910 eachof which is in the shape of a right triangle. Similar to the meshpattern 500 in FIG. 5 , the tiling by the mesh pattern 900 in FIG. 9 isa periodic tiling having a repeating pattern 920. The repeating pattern920 is a rectangle including two right triangles that are side by sidevia a same hypotenuse, which is a diagonal line of the rectangle. Thatis, the mesh pattern 900 can tile the rectangular surface with periodicrectangles each of which is formed by two right triangles.

FIG. 10 illustrates a mesh pattern 1000 that can tile a rectangularsurface of a RF screen with a plurality of individual openings 1010 eachof which is in the shape of a right triangle. Similar to the meshpattern 600 in FIG. 6 , the tiling by the mesh pattern 1000 is aperiodic tiling having a repeating pattern 1020, which is a rectangleincluding 8 right triangles. The 8 right triangles form 4 pairs each ofwhich includes two right triangles that are side by side via a samehypotenuse. That is, the mesh pattern 1000 can tile the rectangularsurface with periodic rectangles each of which is formed by 8 righttriangles.

FIG. 11 illustrates a mesh pattern 1100 that can tile a rectangularsurface of a RF screen with a plurality of individual openings 1110 eachof which is in the shape of a right triangle. Similar to the meshpattern 700 in FIG. 7 , the tiling by the mesh pattern 1100 is aperiodic tiling having a repeating pattern 1120, which is a rectangleincluding 8 right triangles. The 8 right triangles form 4 pairs each ofwhich includes two right triangles that are side by side via a samehypotenuse. That is, the mesh pattern 1100 can tile the rectangularsurface with periodic rectangles each of which is formed by 8 righttriangles.

FIG. 12 illustrates a mesh pattern 1200 that can tile a rectangularsurface of a RF screen with a plurality of individual openings 1210 eachof which is in the shape of a right triangle. Similar to the meshpattern 800 in FIG. 8 , the tiling by the mesh pattern 1200 is aperiodic tiling having a repeating pattern 1220, which is a rectangleincluding 4 right triangles. The 4 right triangles form 2 pairs each ofwhich includes two right triangles that are side by side via a samehypotenuse. That is, the mesh pattern 1200 can tile the rectangularsurface with periodic rectangles each of which is formed by 4 righttriangles.

FIG. 13 illustrates a mesh pattern 1300 that can tile a surface of a RFscreen with a plurality of individual openings 1310 each of which is inthe shape of an isosceles triangle. The tiling by the mesh pattern 1300is a periodic tiling having a repeating pattern 1322. As shown in FIG.13 , the repeating pattern 1322 is a parallelogram including twoisosceles triangles that are side by side via a shared leg, which is adiagonal line of the parallelogram. The repeating pattern 1322 is aminimum pattern element that can be repeated to tile the surface basedmerely on translation of the repeating pattern, without a need ofrotating, reflecting or scaling the repeating pattern. As such, the meshpattern 1300 can tile the surface with periodic parallelograms each ofwhich is formed by two isosceles triangles.

As shown in FIG. 13 , the mesh pattern 1300 comprises a plurality ofrows each of which is formed by periodic cells or periodicparallelograms. In this embodiment, the periodic cells in two adjacentrows are aligned to each other. For example, the mesh pattern 1300includes a first row 1301 formed by periodic parallelograms; andincludes a second row 1302 formed by periodic parallelograms. The firstrow 1301 and the second row 1302 are adjacent to each other. Theperiodic parallelograms of the first row 1301 and the periodicparallelograms of the second row 1302 are aligned to each other, whichmeans they share common sides. For example, the periodic parallelogram1322 of the first row 1301 and the periodic parallelogram 1324 of thesecond row 1302 are side by side via a shared common side. When the RFscreen surface is in the shape of a rectangle as shown in FIG. 13 , eachrow has two right triangles 1330 at the two ends of the row.

FIG. 14 illustrates a mesh pattern 1400 that can tile a surface of a RFscreen with a plurality of individual openings 1410 each of which is inthe shape of an isosceles triangle. The tiling by the mesh pattern 1400is similar to the tiling by the mesh pattern 1300 in FIG. 13 , exceptthat the periodic cells in two adjacent rows are not aligned to eachother in FIG. 14 . For example, the mesh pattern 1400 includes a firstrow 1401 formed by periodic parallelograms; and includes a second row1402 formed by periodic parallelograms. The first row 1401 and thesecond row 1402 are adjacent to each other. The periodic parallelogram1422 of the first row 1401 and the periodic parallelogram 1424 of thesecond row 1402 are not aligned to each other, which means they are notsharing a common side. When the RF screen surface is in the shape of arectangle as shown in FIG. 14 , each row has two right triangles 1430 atthe two ends of the row.

FIG. 15 illustrates a mesh pattern 1500 that can tile a surface of a RFscreen with a plurality of individual openings 1510 each of which is inthe shape of an equilateral triangle. The tiling by the mesh pattern1500 is similar to the tiling by the mesh pattern 1300 in FIG. 13 ,except that the repeating pattern 1522 in FIG. 15 is a diamond includingtwo equilateral triangles that are side by side via a shared side, whichis a diagonal line of the diamond. The periodic cells in two adjacentrows are aligned to each other in FIG. 15 . For example, the periodicdiamond 1522 of the first row 1501 and the periodic diamond 1524 of thesecond row 1502 are aligned to each other, which means they are side byside via a shared common side. When the RF screen surface is in theshape of a rectangle as shown in FIG. 15 , each row has two righttriangles 1530 at the two ends of the row.

FIG. 16 illustrates a mesh pattern 1600 that can tile a surface of a RFscreen with a plurality of individual openings 1610 each of which is inthe shape of an equilateral triangle. The tiling by the mesh pattern1600 is similar to the tiling by the mesh pattern 1500 in FIG. 15 ,except that the periodic cells in two adjacent rows are not aligned toeach other in FIG. 16 . For example, the periodic diamond 1622 of thefirst row 1601 and the periodic diamond 1624 of the second row 1602 arenot aligned to each other, which means they are not sharing a commonside. When the RF screen surface is in the shape of a rectangle as shownin FIG. 16 , each row has two right triangles 1630 at the two ends ofthe row

FIG. 17 illustrates a flow chart of a method 1700 for performing a UVinduced deposition, in accordance with some embodiments of the presentdisclosure. The method begins at operation 1702, where a blower fan of aUV lamp system is turned on. At operation 1704, an input electricalpower is converted to RF energy. At operation 1706, gases in a UV bulbis excited with the RF energy to emit a UV light. The RF energy isscreened with an RF screen comprising triangular openings at operation1708. Then at operation 1710, the UV light is passed through the RFscreen with a higher light transmittance, compared to RF screens withrectangular or hexagonal openings. In one embodiment, the UV lightpasses through the RF screen with a light transmittance greater than70%. In another embodiment, the UV light passes through the RF screenwith a light transmittance greater than 75%. At operation 1712, a gasflow is provided into a processing chamber for UV induced deposition.The order of the operations in FIG. 17 may be changed according tovarious embodiments of the present teaching.

In some embodiments, a radio frequency (RF) screen for a microwavepowered ultraviolet (UV) lamp system is disclosed. The RF screenincludes: a sheet comprising a conductive material; and a frame aroundedges of the sheet. The conductive material defines a predetermined meshpattern of individual openings across substantially an operative area ofthe screen. Each of the individual openings has a triangular shape. Thepredetermined mesh pattern comprises 16 to 36 individual openings perunit area of 1 square centimeter.

In some embodiments, a microwave powered ultraviolet (UV) lamp system isdisclosed. The microwave powered UV lamp system includes: at least onemagnetron configured to convert electrical power received from a powersupply to radio frequency (RF) energy; a UV bulb configured to beexcited by the RF energy to emit UV light; and an RF screen. The RFscreen includes a sheet comprising a conductive material. The conductivematerial defines a predetermined mesh pattern of individual openingsacross. At least one of the individual openings has a triangular shape.

In some embodiments, a method is disclosed. The method includes:converting an input electrical power to radio frequency (RF) energy;exciting a ultraviolet (UV) bulb with the RF energy to emit a UV light;and screening the RF energy with an RF screen comprising a sheet havinga predetermined mesh pattern of individual openings. At least one of theindividual openings has a triangular shape.

While various embodiments of the present disclosure have been describedabove, it should be understood that they have been presented by way ofexample only, and not by way of limitation. Likewise, the variousdiagrams may depict an example architectural or configuration, which areprovided to enable persons of ordinary skill in the art to understandexemplary features and functions of the present disclosure. Such personswould understand, however, that the present disclosure is not restrictedto the illustrated example architectures or configurations, but can beimplemented using a variety of alternative architectures andconfigurations. Additionally, as would be understood by persons ofordinary skill in the art, one or more features of one embodiment can becombined with one or more features of another embodiment describedherein. Thus, the breadth and scope of the present disclosure should notbe limited by any of the above-described exemplary embodiments.

It is also understood that any reference to an element herein using adesignation such as “first,” “second,” and so forth does not generallylimit the quantity or order of those elements. Rather, thesedesignations are used herein as a convenient means of distinguishingbetween two or more elements or instances of an element. Thus, areference to first and second elements does not mean that only twoelements can be employed, or that the first element must precede thesecond element in some manner.

Additionally, a person having ordinary skill in the art would understandthat information and signals can be represented using any of a varietyof different technologies and techniques. For example, data,instructions, commands, information, signals, bits and symbols, forexample, which may be referenced in the above description can berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof.

A person of ordinary skill in the art would further appreciate that anyof the various illustrative logical blocks, modules, processors, means,circuits, methods and functions described in connection with the aspectsdisclosed herein can be implemented by electronic hardware (e.g., adigital implementation, an analog implementation, or a combination ofthe two), firmware, various forms of program or design codeincorporating instructions (which can be referred to herein, forconvenience, as “software” or a “software module), or any combination ofthese techniques.

To clearly illustrate this interchangeability of hardware, firmware andsoftware, various illustrative components, blocks, modules, circuits,and steps have been described above generally in terms of theirfunctionality. Whether such functionality is implemented as hardware,firmware or software, or a combination of these techniques, depends uponthe particular application and design constraints imposed on the overallsystem. Skilled artisans can implement the described functionality invarious ways for each particular application, but such implementationdecisions do not cause a departure from the scope of the presentdisclosure. In accordance with various embodiments, a processor, device,component, circuit, structure, machine, module, etc. can be configuredto perform one or more of the functions described herein. The term“configured to” or “configured for” as used herein with respect to aspecified operation or function refers to a processor, device,component, circuit, structure, machine, module, signal, etc. that isphysically constructed, programmed, arranged and/or formatted to performthe specified operation or function.

Furthermore, a person of ordinary skill in the art would understand thatvarious illustrative logical blocks, modules, devices, components andcircuits described herein can be implemented within or performed by anintegrated circuit (IC) that can include a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device, orany combination thereof. The logical blocks, modules, and circuits canfurther include antennas and/or transceivers to communicate with variouscomponents within the network or within the device. A processorprogrammed to perform the functions herein will become a speciallyprogrammed, or special-purpose processor, and can be implemented as acombination of computing devices, e.g., a combination of a DSP and amicroprocessor, a plurality of microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suitableconfiguration to perform the functions described herein.

If implemented in software, the functions can be stored as one or moreinstructions or code on a computer-readable medium. Thus, the steps of amethod or algorithm disclosed herein can be implemented as softwarestored on a computer-readable medium. Computer-readable media includesboth computer storage media and communication media including any mediumthat can be enabled to transfer a computer program or code from oneplace to another. A storage media can be any available media that can beaccessed by a computer. By way of example, and not limitation, suchcomputer-readable media can include RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to store desired programcode in the form of instructions or data structures and that can beaccessed by a computer.

In this document, the term “module” as used herein, refers to software,firmware, hardware, and any combination of these elements for performingthe associated functions described herein. Additionally, for purpose ofdiscussion, the various modules are described as discrete modules;however, as would be apparent to one of ordinary skill in the art, twoor more modules may be combined to form a single module that performsthe associated functions according embodiments of the presentdisclosure.

Various modifications to the implementations described in thisdisclosure will be readily apparent to those skilled in the art, and thegeneral principles defined herein can be applied to otherimplementations without departing from the scope of this disclosure.Thus, the disclosure is not intended to be limited to theimplementations shown herein, but is to be accorded the widest scopeconsistent with the novel features and principles disclosed herein, asrecited in the claims below.

What is claimed is:
 1. A radio frequency (RF) screen, comprising: a sheet comprising a conductive material; and a frame around edges of the sheet, wherein the conductive material defines a predetermined mesh pattern of individual openings across substantially an operative area of the screen, wherein each of the individual openings has a triangular shape, and wherein the predetermined mesh pattern comprises 16 to 36 individual openings per unit area of 1 square centimeter.
 2. The RF screen of claim 1, wherein: each of the individual openings is in a shape of an isosceles triangle.
 3. The RF screen of claim 2, wherein: the predetermined mesh pattern tiles a surface of the sheet with periodic parallelograms each of which is formed by a plurality of isosceles triangles.
 4. The RF screen of claim 1, wherein: each of the individual openings is in a shape of an equilateral triangle.
 5. The RF screen of claim 1, wherein: each of the individual openings is in a shape of a right triangle.
 6. The RF screen of claim 5, wherein: the predetermined mesh pattern tiles a surface of the sheet with periodic rectangles each of which is formed by a quantity of right triangles.
 7. The RF screen of claim 6, wherein: the quantity is: 2, 4 or
 8. 8. The RF screen of claim 1, wherein: the predetermined mesh pattern comprises a plurality of rows each of which is formed by periodic cells comprising at least one triangle; and the periodic cells in at least two adjacent rows are not aligned to each other.
 9. The RF screen of claim 1, wherein: the individual openings have shapes of multiple types of triangles; and the multiple types of triangles comprise at least one of: an isosceles triangle, a right triangle, an equilateral triangle, or a scalene triangle.
 10. The RF screen of claim 1, wherein: the sheet has a thickness between 0.001 inch and 0.015 inch.
 11. A microwave powered ultraviolet (UV) lamp system, comprising: at least one magnetron configured to convert electrical power received from a power supply to radio frequency (RF) energy; a UV bulb configured to be excited by the RF energy to emit UV light; and an RF screen, wherein the RF screen comprises: a sheet comprising a conductive material, wherein the conductive material defines a predetermined mesh pattern of individual openings across, wherein at least one of the individual openings has a triangular shape, and wherein the predetermined mesh pattern comprises 16 to 36 individual openings per unit area of 1 square centimeter.
 12. The microwave powered UV lamp system of claim 11, wherein: at least one of the individual openings has a rectangular shape.
 13. The microwave powered UV lamp system of claim 11, wherein: the sheet has a rectangular surface with four edges; and the predetermined mesh pattern tiles the rectangular surface of the sheet with a plurality of triangles in proximity of the four edges and a plurality of rectangles surrounded by the plurality of triangles.
 14. The microwave powered UV lamp system of claim 11, wherein: the RF screen is configured to yield an increase in UV light transmittance compared to a reference screen with a mesh pattern comprising individual openings each of which is in a shape of: a square, a rectangle, or a hexagon; and the RF screen and the reference screen have a same number of individual openings in a unit area.
 15. The microwave powered UV lamp system of claim 11, wherein: the RF screen is configured to yield a decrease in maximum deformation compared to a reference screen with a mesh pattern comprising individual openings each of which is in a shape of: a square, a rectangle, or a hexagon; and the RF screen and the reference screen have a same number of individual openings in a unit area.
 16. The microwave powered UV lamp system of claim 11, wherein: the RF screen is configured to yield a decrease in maximum stress compared to a reference screen with a mesh pattern comprising individual openings each of which is in a shape of: a square, a rectangle, or a hexagon; and the RF screen and the reference screen have a same number of individual openings in a unit area.
 17. The microwave powered UV lamp system of claim 11, wherein: the conductive material comprises copper, brass, stainless steel, tungsten, aluminum, nickel, silver, or combinations thereof.
 18. A method, comprising: converting an input electrical power to radio frequency (RF) energy; exciting a ultraviolet (UV) bulb with the RF energy to emit a UV light; and screening the RF energy with an RF screen comprising a sheet having a predetermined mesh pattern of individual openings, wherein at least one of the individual openings has a triangular shape, and wherein the predetermined mesh pattern comprises 16 to 36 individual openings per unit area of 1 square centimeter.
 19. The method of claim 18, further comprising: passing the UV light through the RF screen with a light transmittance greater than 70%.
 20. The method of claim 18, wherein: passing the UV light through the RF screen with a light transmittance greater than 75%. 